Betting Odds Explained

Betting Odds Beginners Guide

If you are new to betting, learning how to understand, and find value in betting odds is a fundamental skill. In this guide, we will explain the three most common betting odds formats, and teach you how to work out the implied probability the betting odds represent. All the top betting sites listed on BettingGuide.com use three different formats for betting odds, Decimal, Fractional, and American.

Decimal Betting Odds

Decimal betting odds are the default format for most online betting sites in Ireland, and they are also our recommended format. The decimal odds represent the potential returns of the bet including the stake. Multiply the decimal odds by the amount you wish to bet to work out your potential return, and minus your stake to calculate the profit.

(Decimal odds x stake = returns - stake = profit)

Example: 2.50 x 100 = 350 - 100 = 250 profit

Fractional Betting Odds

Fractional betting odds are common in English speaking countries, with the United Kingdom using fractional odds as the default setting for most gambling sites. There is a simple way of understanding fractional betting odds.

Example: 3/1 = How much you win/how much you stake

For every €100 you stake, you'll win €300—simple as that.

1/5 = For every €500 you stake, you'll win €100.

American Betting Odds

American, or Moneyline odds, are shown as positive (+) or negative (-) numbers. The positive numbers show how much you might profit if you bet 100, and the negative number shows what you must stake to win 100. We do not recommend using the American style betting odds, but if you find it easier, most online betting sites offer the Moneyline odds format as an option.

Calculating Implied Probability

Odds reflect the implied probability of an event occurring, and it is important to know how to change the odds into a percentage to work out if there is value in the bet. We recommend using decimal odds, as you just need to divide 100 by the decimal odds to work out the percentage.

Example: 100/2.50 = 40%

Let's say, two football teams have seen both teams score in a combined average of 70% of their games.

If both teams to score was set at 2.50 (40%), there would be value in the odds offered compared to the 70% average.